Robust data link protocols for connection-less service over satellite links

The performance of the connection-less network service (CLNS) over a satellite link with features such as high propagation delay and a varying (often high) level of errors, can be improved using the connection oriented data link (CODL) service. However, although existing CODL protocols satisfy the requirements of a connection oriented network protocol (e.g. X.25), they are not optimal for the CLNS over satellite links. The interaction of link error recovery procedures with the error recovery procedures implemented by CLNS users, the unnecessary delay due to link protocol sequencing and recovery procedures, and the interaction between applications with different quality of service (QoS) requirements cause most CODL protocols to have a detrimental impact on the performance of the CLNS. This study presents a new link protocol, which improves the quality of the CLNS (e.g. IP), especially considering the enhancement of the performance of connection-oriented transport protocols (e.g. TCP). The performance improvement using the new link protocols is demonstrated by implementation in a satellite interworking unit.